To estimate aerodynamic coefficients that indicate the aerodynamic characteristics of an aircraft, a method in which information such as the angle of attack, the angle of sideslip, the airspeed, the angular speed, the attitude angle, and the deflection angle is acquired from various sensors provided on the aircraft and computation by an iterative least square technique or a neural network technique is performed based on the acquired information is known. Moreover, a method of detecting a failure of or damage to control surfaces by comparing the thus estimated aerodynamic coefficients with the aerodynamic coefficients of the aircraft in a normal state is known.
For example, Patent Literature 1 (Japanese Unexamined Patent Application, Publication No. 2003-175896) discloses a control surface failure/damage detection device that estimates aerodynamic coefficients using the iterative least square technique, performs computation on the estimated aerodynamic coefficients using the neural network technique to calculate final aerodynamic coefficients, and detects a failure or the like of control surfaces by software based on the calculated final aerodynamic coefficients.
Also, a method in which hardware such as an optical fiber or an electric wire is laid on an aircraft to directly detect damage to control surfaces is conceivable.